June 11, 2013
Shamika Smith, MPH
Epidemiologist
City of Chicago
Mayor Rahm Emanuel
Chicago Department of Public Health
Commissioner Bechara Choucair, M.D.

• Bacteria ubiquitous in environment, typically water
• Transmitted through aerosolization or aspiration of Legionella -contaminated water
• Immunocompromised individuals are most susceptible

Legionnaires' disease
(LD)
Pontiac Fever
(PF)
Clinical features
Radiographic pneumonia
Pneumonia, cough, fever Flu-like illness (fever, chills, malaise) without pneumonia
Yes No
Incubation period
Etiologic agent
2-14 days after exposure 24-72 hours after exposure
Legionella species Legionella species
Attack rate
Isolation of organism
< 5%
Possible
> 90%
Never
Outcome Hospitalization common
Case-fatality rate: 5-30%
Hospitalization uncommon
Case-fatality rate: 0%
CDC. Top 10 Things Every Clinician Needs to Know About Legionellosis. 2013. Retrieved from http://www.cdc.gov/legionella/clinicians.html

Reported Legionellosis Case Counts, 1990-2011*
United States (CDC )
3000
2000
1000
0
160
120
80
40
Illinois (IDPH)
0
50
40
30
20
Chicago (CDPH)
10
0
90 91 92 93 94 95 96 97 98 99 00 01 02 03 04 05 06 07 08 09 10 11
*Counts for U.S. (2011) not yet published .

Reported Legionellosis cases by month of onset,
Chicago, 2001 - 2010
September 2006
N=12
August 2007
N=14
Reported residences of cluster casepatients
June-Aug. 2010
N=18

• Aug. 14, 2012: Company A contacted CDPH reporting:
--30 cases of respiratory illness
--several cases of pneumonia; 1 death
• CDPH contacted Hotel X-learned that guest (not Company
A) also reported illness
• Conference held at Hotel X from Jul. 30- Aug. 3
-- Approximately 600 attendees
-- Event I (7/30-8/1): 427 people
-- Event II (8/2-8/3): 266 people
-- 80 people attended both event

22
29
5
12
19
26
Sunday
JULY 15
Monday Tuesday Wed Thursday Friday Saturday
16 17 18 19 20 21
23
30
6
13
20
27
24
31
7 8
14 CDPH notified
21
15
22
25
AUG 1
28 29
26
2
9
16
23
30
27
3
10
17
24
31
28
4
11
18
25

22
29
5
12
19
26
Sunday
JULY 15
Monday Tuesday Wed Thursday Friday Saturday
16 17 18 19 20 21
23
30
6
13
20
27
24
31
7 8
14 Water
Closures
21
15
22
25
AUG 1
28 29
26
2
9
16
23
30
27
3
10
17
24
31
28
4
11
18
25

22
29
5
12
19
26
Sunday
JULY 15
Monday Tuesday Wed Thursday Friday Saturday
16 17 18 19 20 21
23
30
6
13
20
27
24
31
25
AUG 1
7 8 9
14 Water
Closures
21
15 Water
Drained
22
16
23
26
2
28 29 30
27
3
10
17
24
31
28
4
11
18
25

• Hotel reached out to guests 7/16-8/15
--Earliest exposure date: 7/26- 10 days= 7/16
--The day fountain, pool, spa drained: 8/15
• CDPH contacted other hotel event organizers
• Hotel unable to obtain mailing addresses for ~40% of guests by 8/20
• Three press releases; media interviews

Methods: Survey Development
• Exploratory interviews with Company A employees
• Etiology unknown, therefore reviewed
– Legionella questionnaire
– CDC’s acute respiratory illness questionnaire
• Piloted draft questionnaire, 8/15 (morning)
• Questionnaire sent to all Company A hotel guests via
Health Alert Network (HAN), 8/15 (afternoon)

19
26
22
29
5
12
Sunday
JULY 15
Monday Tuesday Wed Thursday Friday Saturday
16 17 18 19 20 21
20
27
23
30
6
13
24
31
25
AUG 1
7 8 9
14 CDPH notified
21
15 Survey
EPI-X
Sample 1
22
16
23
26
2
28 29 30
24
31
27
3
10
17
28
4
11
18
25

Health
• Illinois Department of Public Health (IDPH),
Environmental Health inspected/sampled:
– Whirlpool spa
– Indoor pool
– Fountain in lobby
– Locker rooms
– Steam room
– Sauna
– Guest shower heads
• CDC consulted

19
26
22
29
5
12
Sunday
JULY 15
Monday Tuesday Wed Thursday Friday Saturday
16 17 18 19 20 21
20
27
23
30
6
13
24
31
25
AUG 1
7 8 9
14 CDPH notified
21
15 Survey
EPI-X
Sample 1
22
16
23
26
2
28 29 30
27
3
28
4
10 11
17 Data analysis
18
Sample 2 Sample 3
24 25
31

Case
• Fountain exposure significantly associated with illness
• Case definition: hospitalized, pneumonia dx, chest x-ray ordered
Yes
No
Fountain Exposure
Yes
13
51
64
No
7 20
99 150
106 170
P-value=.0074

40
30
20
10
0
70
60
50
80
Dates of press releases

HAN Survey Results and
Data from CDPH Phone Bank
HAN Survey from Company A
• 328 responses, ~ 1/3 reporting illness
• 1 confirmed case (1 expired)
Phone Bank
• 145 surveys completed, most reporting illness
• 10 confirmed cases (2 expired)

Confirmed Legionnaires’
Disease (LD)
Case definition: A person who stayed at or visited the hotel with illness onset within 2-14 days of exposure to the hotel, AND with radiographically- or autopsyconfirmed pneumonia AND with laboratory evidence of
Legionella infection.

Confirmed LD Laboratory
Criteria
• Isolation, through culture, of any Legionella organism from resp. secretions, lung tissue, pleural fluid, or other normally sterile site
• Detection of Legionella pneumophila serogroup 1
(Lp1) antigen in urine
• Seroconversion (4-fold increase in antibody titer to
Lp1 between acute and convalescent titers)
• Detection by Lp1 molecular testing (e.g., PCR)

Suspect Legionnaires’ Disease
Case definition: A person who stayed at or visited the hotel with illness onset within 2-14 days of exposure to the hotel, who had radiographically- confirmed pneumonia, or clinical diagnosis of pneumonia, but without laboratory confirmation of
Legionella infection.

Pontiac Fever
Case definition: Fever, either subjective or documented, in a person who stayed at or visited the hotel with illness onset within 3 days of exposure to hotel, AND at least one of the following: cough, headache, SOB, myalgias, diarrhea, or vomiting, and who does not meet definition for confirmed or suspect LD.

10
5
25
Respiratory Illness by Date of Symptom Onset
(N=114)
Legionnaires disease confirmed
Legionnaires disease suspect
20
Pontiac Fever
Case fatality
15
CDPH notified Fountain, pool and spa drained
0
21 23 25 27 29 31 2 4 6
July
8 10 12 14 16 18 20 22
August

% Male
All cases (N=114) Confirmed LD (N=11)
64 91
Median age
(range)
% Hospitalized
Deaths
Underlying illness/ risk
47 yrs (22-82 yrs) 65.5 yrs (49-82 yrs)
13
0
N/A
82
3
Obesity (1), HIV (1), COPD
(1), HTN/CVD (5), current/former smokers
(2/2)

Casepatients’ Symptoms
Symptoms (n/N)
All cases
%
Confirmed LD
(n/N) %
Fever
Cough
Shortness of
Breath
Vomiting or
Diarrhea
113/114
76/110
65/107
57/105
99
69
61
54
10/11
9/10
8/10
5/11
91
90
80
45

Exposure Assessment (106 ills, 194 wells)
Exposure
Lobby Fountain
Lobby Bar
Whirlpool Spa
Pool
Sauna
Steam Room
Guest Shower
Guest Bath
# Exposed
123
211
5
4
3
4
236
50
RR(CI)
2.13 (1.64, 2.77)
1.25 (1.09, 1.44)
2.38 (0.40, 13.99)
4.76 (0.50, 45.10)
0.79 (0.07, 8.63)
1.59 (0.23, 11.08)
1.00 (0.92, 1.07)
0.89 (0.53, 1.50) p
<0.0001
0.003
0.378
0.302
1.000
0.322
0.899
0.666

• Positive: Lobby fountain, locker rooms (men and women shower heads and sinks), swimming pool, whirlpool
• Negative: Guest room shower heads

• Lp1 environmental isolates and a clinical isolate from a confirmed LD case-patient had matching sequence-based types.

Contributing Factors to
Legionella Growth in Fountain
• Lack of written cleaning and maintenance program
• Presence of submerged lighting
• Presence of dirt, organic matter, or other debris in the water basin

• Fountain removed
• Installation of chlorine dioxide treatment system to water supply
– Must keep monthly operational records
– IDPH inspection every 2 years

• Point source outbreak
• Environmental testing identified Legionella in the hotel’s potable water system.
• Poor fountain maintenance likely created favorable conditions for Legionella overgrowth
• Epidemiologic and molecular typing data confirmed that fountain was likely the source

Acknowledgements
• Centers for Disease Control and Prevention
– National Center for Immunization and
Respiratory Diseases, Division of Bacterial
Diseases
• Illinois Department of Public Health
– Craig Conover, MD, MPH
– Connie Austin, DVM, PhD
– Division of Environmental Health
– Division of Infectious Diseases

Acknowledgements
• AL, AR, AZ, CA, CO, FL, GA, IA, IN, KS, MA, MD,
ME, MI, MN, MO, NC, NE, NJ, NY, OH, OR, PA, TN,
TX, VA, WI, WV, Ireland, Canada
• Chicago Department of Public Health
– Communicable Disease Program
– Emergency Preparedness Program

@ChiPublicHealth facebook.com/ChicagoPublicHealth
312.747.9884
HealthyChicago@CityofChicago.org
www.CityofChicago.org/Health

Public health Messaging
• IDPH Environmental laboratory results
• Exposures eliminated
– Fountain removed
– Pool, spa, locker rooms inaccessible to public
• Updating case counts

Legionellosis cases by month of onset, 2011-2012
20
15
10
5
0
JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC

SU M TU W TH F SA
Jul y 16 17 18 19 20 21
22 23 24 25 26 27 28
29 30 31 1 2 3 4
A u g u st
5 6 7 8 9 10 11
12 13 14 15 16 17 18
19 20 21 22 23 24 25

SU M TU W TH F SA
Jul y 16 17 18 19 20 21
22 23 24 25 26 27 28
29 30 31 1 2 3 4
A u g u st
5 6 7 8 9 10 11
12 13 14 15 16 17 18
19 20 21 22 23 24 25

Reported cases per
100,000 adults
Reported 10-year incidence rates per
100,000 adult residents, by Chicago community area, 2001-August 2010
Approximate reported residence of
Chicago case-patients, with spatial clustering denoted in gray

Casepatients’ Characteristics
% Male
Median age (range)
% Hospitalized
Deaths
Underlying Illness/risk
All Cases (N=114)
64
47 (22-82 yrs)
13
0
N/A
Confirmed LD (N=11)
91
65.5 (49-82 yrs)
82
3
Obesity(1), HIV(1),
COPD(1), HTN/CVD(5), current/former smokers
(2/2)

Bakery re-opening
Inspection and product recall
Bakery closure
July
= outbreak
29 30 3 1
August
12 18 22 23 30

• Increasing population of older persons
• Increasing population of persons at high risk for infection
• Improved diagnosis and reporting
• Weather conditions..

19
26
22
29
5
12
Sunday Monday Tuesday Wed Thursday Friday
JULY 15 16 17 18 19 20
20
27
23
30
6
13
24
31
7
14 CDPH notified
21
8
15
22
25
AUG 1
28 29
23
30
26
2
9
16
24
31
27
3
10
17
28
4
11
18
25
Saturday
21

Sunday Monday Tuesday Wed Thursday Friday
July 16 17 18 19 20
Saturday
21
5
12
19
26
22
29
6
13
20
27
23
30
24 25
31
7
14 CDPH notified
21
1
August
8
15
22
28 29
9
16
23
30
26
2
10
17
24
31
27
3
11
18
25
28
4

SU M TU W TH F SA
Jul y 16 17 18 19 20 21
22 23 24 25 26 27 28
29 30 31 1 2 3 4
A u g u st
5 6 7 8 9 10 11
12 13 14 15 16 17 18
19 20 21 22 23 24 25

SU M TU W TH F SA
Jul y 16 17 18 19 20 21
22 23 24 25 26 27 28
29 30 31 1 2 3 4
A u g u st
5 6 7 8 9 10 11
12 13 14 15 16 17 18
19 20 21 22 23 24 25

SU M TU W TH F SA
Jul y 16 17 18 19 20 21
22 23 24 25 26 27 28
29 30 31 1 2 3 4
A u g u st
5 6 7 8 9 10 11
12 13 14 15 16 17 18
19 20 21 22 23 24 25

SU M TU W TH F SA
Jul y 16 17 18 19 20 21
22 23 24 25 26 27 28
29 30 31 1 2 3 4
A u g u st
5 6 7 8 9 10 11
12 13 14 15 16 17 18
19 20 21 22 23 24 25